The invention relates to a method of bonding a surface of a metal oxide or a metal oxidic compound to a contact metal, the contact metal being brought into contact with the surface of the metal oxide or the metal oxidic compound.
A metal oxidic compound is to be understood to mean herein an oxidic compound of at least two metallic elements such as, for example, nickel ferrite NiFe.sub.2 O.sub.4. Because of their magnetic properties ferrites are important ceramic compounds. Ferrites are used, inter alia, in magnetic heads for the purpose of magnetic recording. A thin non-magnetic metal layer is often applied between the two halves of the magnetic head, which metal layer serves as a so-called spacer.
Such a method is described in U.S. Pat. No. 3,793,705, in which titanium or chromium are applied to a ferrite by means of sputtering. Subsequently, the chromium layer is provided with a silver-containing brazing alloy. A non-magnetic metal is brought into contact herewith and the assembly is subsequently fired in an inert atmosphere, the bond between metal and ferrite being formed via the intermediate layer of chromium and the brazing alloy.
A disadvantage of the known method is that metals such as titanium and chromium react With the oxygen present in the sputtering gas or residual gas instead of with the oxygen of the metal oxidic compound, as a result of which the bonding of these metals to the metal oxide is insufficient. Moreover, a brazing alloy is required for the bonding to a second non-magnetic metal. The brazing alloy may interact undesirably with the bonding layer and/or the metal layer.